Controls for turret lathes and the like



June 22, 1965 A. G. KOZACKA 3,190,151

CONTROLS FOR TURRET LATHES AND THE LIKE Original Filed Jan. 30, 1958 4 Sheets-Sheet 1 o I m l i I J 1: I m i 1 i k i i L 1,1 L\ km be R N 2 5 1 i z'ih:

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June 22, 1965 A. G. KOZACKA 3,190,151

CONTROLS FOR TURRET LATHES AND THE LIKE Original Filed Jan. 30, 1958 4 Sheets-Sheet 2' June 22, 1965 A. G. KOZAC KA Original Filed Jan. 30, 1958 4 Sheets-Sheet 3 k. 2 if 62 5-E 26% ZQQ.

4 Sheets-Sheet 4 A. G. KOZACKA CONTROLS FOR TURRET LATHES AND THE LIKE I I I CV E e z z E P H E 2 F E H R Li 0 D 7 F T M P 5 0 M 1 fir F mlw w 7 z m W Li, M M y a 9 i w H a M T x E H L n 6 J IM 3 w F 1? H "m 0 w P D D D 1|=|.. N P 1 5 H} w m p w w m w z i a Q a m is Y H m D. .M. M 6 E FIILIL W p 1 H a I. 1 T m 2 W 2 P W r. r l c L M w 2 m p c H e r} 2 N 4 E .w 1 W 12 Ill j i w W m E A A June 22, 1965 Original Filed Jan. 30, 1958 CONTROLS FOR TURRET LATI-EES AND THE LEE Arthur G. Kozacka, Chicago, IIL, assignor to Acme lndustrial Company, Chicago, 111., a corporation of Illinois Original application Jan. 30,1958, Ser. N 712,263, new

Patent No. 3,060,466, datedOct. 30, 1962. Divided and this application Mar. 7, 1962, Ser. No. 180,926

2 Claims. (Cl. 77-'3 2.5)

The present application is a division of my copending application Serial No. 712,263, filed January 30, 1958, entitled Controls for Turret L-athes and the Like,-now Patent No. 3,060,466 granted October 30, 1962.

The present invention relates in general to machine tools, and to the control of reciprocatable machine tool elements. More particularly, the invention has to do with controlling the motions of reciprocatable, rotationally indexable machine tool elements, such as the turret of a turret lathe. l V

So-called automatic control systems for lathe turrets have long been known and have taken a variety of forms. Such prior systems have been limited, however, to carrying out a limited number of different operational cycles, and have been complex in organization and inconvenient in set-up to accomplish a certain cycle when the turret is at a selected station. In short, prior systems have not been fully automatic in that they could not automatically bring about any selectedone of a large plurality of different operational cycles when the turret is in any of its several indexed stations.

The general aim of this invention is to bring forth an improved system for controlling the motions of a lathe turret or the like, a system which affords pre-programm-ing or preselection of any one of a fairly large number of operational cycles to take place when the turret is at anyone of its indexed stat-ions.

Another object of the invention is to provide such a system which is relatively simple in its organization, and in which the control components for bringing about one type of operational cycle are utilized by modifying interconnections to effect other cycles of operation.

A more specific object of this invention is to provide a lathe turret control which can produce the usual standard cycle of turret movement, yet in which a dwell periodmay be individually adjusted and preselected for each station of the turret.

Other objects and advantages will become apparent as the following description proceeds, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a front elevation of a turret lathe equipped with a control system embodying the features of the present invention;

FIG. 2 is an enlarged elevation corresponding to a part of FIG. 1;

FIG. 3 is a plan view, taken partly in section substantially along the line 3-3 in FIG. 2;

FIG. 4 is a detail view in section, taken substantially along the line 4-4 in FIG. 3;

FIG. 5 is a detail view in section, taken substantially along the line 55 in FIG. 3 and showing the arrangement of traverse and feed control dogs;

FIG. 6 is a vertical sectional view of a part of the apparatus employed to produce a reciprocating drilling cycle of turret movement; 7 y

' 'FIG. 7 is a schematic diagram of the hydraulic circuits of the control system; i

FIG. Sis a schematic diagram of the electrical circuits of the control system; and

FIG. 9 is a schematic diagram of electrical connec-,

tions for producing individually adjustable dwell periods at each turret station. V

While .the invention has been shown and'will be de- United States, Patent O icescribed in some detail with reference to a particular embodiment thereof, there is no intention that it thus be limited to such detail. On the contrary, it is intended here to cover all alterations, modifications, and equivalents falling Within the spirit and scope of the invention as defined by the appended claims.

Referring now to the drawings, the invention has been shown by Way of example as applied to .a turret lathe 10 (FIG. 1) which includes the usual headstock 11 mounted at one end of a bed 12 and supporting a rotatable work-holding chuck 14. The lathe also. has a turret 15 'movable along .a linear path, that turret being here shown as mounted on a slide 16 which slides alougways 18 formed on the bed 12.

The turret 15 as here illustrated is rotatable about a vertical axis relative to the slide 16, and provided with a plurality of angularly spaced, socketed faces for receiving various types of cutting tools. For example, the turret 15 may have-six socketed faces therearound and may receive drills, boring cutters, reamers, thread-cutting dies, or similar tools in its sockets for performing different machining operations successively on a single workpiece held in the chuck 14.

To rotationally index the turret 15, and thus bring its faces successively into alinement opposite the chuck 14, the slide 16 includes a conventional indexing mechanism, which is not illustrated in detail. Such indexing mechanisms are well known to those skilled in the art and opcrate to index the turret 15 to its next rotational station as an incident to the turret and slide 16 being fully reracted away from the chuck 14. It will be sufiicient to note here simply that the turret has a shaft 15a projecting therefrom which is so connected with the indexing mechanism that it rotates in step with the turret 15 when the latter is indexed from one station to the next.

For advancing the turret 15 forwardly toward the chuck 14 or retracting the turret rearwardly away from the chuck, reversible power means are utilized. In the form here illustrated, such reversible power means is constituted by a double-acting hydraulic actuator 20 which includes a cylinder 20a mounted at the right end of the bed 12, and a piston 29b slidable within that cylinder (FIG. 7). A piston rod 29c is rigidly connected at its left end with a yoke 21 fixed to the slide 16, so that as the piston 20b moves forwardly and rearwardly, the slide and the turret thereon are correspondingly advanced and retracted along the bed 12.

For supplying energy to the reversible hydraulic actuaa solenoid controlled direction-controlling valve 26. Fluid can pass to or from the opposite ends of the cylinder 20a through conduits 27 and 28, such fluid flowing under pressure from the pump 22 or returning to the sump 24 through a line 29. Connected in the line 28 is a rate valve as which by varying the size of the orifice or restriction which it presents, determines the speed or. rate at which the piston 29b moves fora given output pressure from the pump 22.

Controls and operation for standard cycle For the normal or standard cycle of turret movement, it is desired to advance the turret 15 forwardly toward the work in the chuck 14 at a rapid traverse rate in order to minimize the time required to bring the cutter tool into engagement with the workpiece.

After 4 the turret has advanced rapidly through a first predetermined distance 1 to present the cutter tool to the workpiece, it is then desired to move the turret forwardly for a second predetermined distance at a relativelyslow or feed rate during the actual cutting engagement of the tool' with the WOIkPlfiCB..

When the turret reaches the end of this second predetermined distance, i.e., when the cutter tool carried by the turret reaches the end of the su'rface'it is to act upon, then it is desired to'reverse the motion of the turret and move it rapidly to'its fully retracted orhome position. This'retraction causes the indexing mechanism to rotationally advance the turret to its next station, presenting thenext cutting tool thereon in operative position to engage the workpiece when the turret is advanced again.

To bring about such a standard cycle ofturret movement, the reversing valve26 (FIG. 7) is employed to control the direction of turret movement. Thisvalve includes a plunger 2611 having three lands movable within a valve casing zfib and centered by means such as com pression springs 260. With the plunger centered, the valve ports connecting with a pressure conduit 32 and the actua tor conduits 27 and 28 areshutoff. Accordingly, the piston 2% and the turret 15 are hydraulicallylocked against movement. Associated with the plunger 26a are two sole acids, a forward solenoid S-F and a reverse solenoid SR,

. r 4, sion is made toselect individually for each station of the turret the first predetermined distance through which the turret will advance at atraverse rate, the second predetermined distance through which rit will advance at a'feed. 'rate before reversing, .and the value or magnitude of; that feed rate. To accomplish this, the right end of the indexc-d turret shaft 15a is journaled in the yoke 2 1 (-FIG. 2) and carries a gear 37 meshed with a pair of gears 38 and 39 '(FIG. 3). The latter gears are mounted on shafts 40 and 41 which arealso journaled in the yoke 21. It will be apparent, therefore, that as the turret and its shaft 15d V are. successively rotated in steps for indexing, the shafts 4t} and 41 will likewise be rotationally'indexedn The shaft 40 isslidably supported at its right end (FIG. 3) in a bracket 44 fixed to the lathe bed, so" that this'shaft is not only rotationally indexed in step with the turretbut I also moves longitudinally therewith. As illustrated best in FIG. 5, theshaft 40' is provided withsix angularly spaced ribs Mia-40f corresponding in their locations to the six angular stations of the turret 15. For controlling the firstidistance through which the turret advances Ma When solenoid 8-,? is energized to shift the plunger za to the left, then. the landson the plunger move so that pressure fluid flows from the line 32 through holes inthe center land to the line 27, supplying fluid pressure to the right end of the c llinderzfta. At the same time, the plunger lands place the line 23 in communicationwith venting conduits 29a and 29, so that tluid canpass from the left end of the cylinder 29a back to the sump 24. Under these conditions, the piston 29b and the turret 15 will advance forwardly, i.c., toward thework-holding chuck 14."

Onthe other hand, when the reversing solenoid S'-R; is I energized to shift the plunger 26a to the right, then the plunger lands will place the lines 32 and 23 in communication so that fluid under pressure flows from the pump 22 to the left end of the cylinder 29a. Correspondingly, the lands on the plunger 26a place the lines Hand 2% in communication so that fiuid can passfrom the right end of thecylinder 23 to thesump 24; 'Under these eonditions, the piston Zilb and'the turret 15will'move rearwardly, i.e., away from the work-holding chuck 14.

As previously noted, the rate valve 39 is used to control the. speed withwhich the piston Ziib and the turret 15 move. As shown in FIG. 7, the rate valve ineludes'a plunger 36:: shiftable in a valve body 3%. The plunger 0 has an orifice therein which may be alined to difierent de- The valve is normally held in a wide-open'condition by energization of an associated solenoid S-RT which shifts the valve plunger 3%?! to the left against the'bia'sing force of a compression spring 300.. Thus, when the solenoidS-RT is energized, the valve 3t} presents substantially no restriction'in line 23'and the piston 2%!) moves at a rapid traverse rate. However, when'the solenoid SeRT is (leenergized, then the spring Stic'urges the plunger 32a to traverse rate, each of these ribsreceives a longitudinally adjustable dog 45 (FIG. 2) which is so sized and'posi- I tioned when its mounting rib is in the uppermost position as to engage and deflect (as the shaft 40 moves longitudik nally) a roller 46 connected by a suitablelinkage to ac;-

tuate a control switch CSFD. This feedicontrol switch,

- as will be later explained, serves when actuated to convert the velocity of turret movement from traverse rate to feed rate. And it will be readily apparent that the point at which forward traversing endsand forward feeding begins may be individually preselected for each of the several turret stations by adjusting the positions of the several dogs lengthwise along the shaft 40. 'The feed control switch IS-FD is carried on the upper portion of a bracket-48 rigidly fixed to the lathe bed 12 j 7 In a similar manner, the shaft 40 is provided withan axialiy'adjustable dog 49 on each'of its angularly spaced "ribs. As shownbestinFIG. 5, each dog ,49- includes a split finger49aadapted tobe clamped to one of the'shaft ribs by means of a screw 49b,-.and which carries at its" upper end athreaded adjustable screw 490. Thus, each of the dogs 49 may be bodily adjusted and then locked in its position lengthwise of the shaft 40, and the forward end of the screw 490 may be precisely adjusted to adesired position by turning that screw within the finger 49a.

The forward or'left ends of the screws 490 as viewed in FIG. 2 are so located as to engage a finger50 (cleared by the dogs 45) asfthe turret advances to a predetermined point, that finger being connected to actuate a reversing control 'switchCS-R. This latter switch, as will be ex- 'plained below, funetions when actuated to reverse the, a

direction of turret movement.

1 The shaft 41 (FIG. 3 ),which is indexed in step wit the turret, is splinedand is axially slidable within ahollow mating sleeve 52. The sleeve 52 is journaled in the brackets44-and 48 and will thus be rotationallyindexed in step i with the turret'while remaining axially'stationary To enable the individual selection of feed rates for each station ofthe-turret, the disk 36 is mounted'on the right'end z of the sleeve 52 (FIG. 3) anclcarries the several angu- 7 larly spaced stop screws 35so that a diiferentonewill be theright (FIG. 7), its position being determined by one of a plurality of stop screws 35 carried by a rotatable disk 36 Since this partially closes down the restriction afforded by the valve 39, the piston 29b then moves at a slower, feed rate.' The exact valueof this feed 'rateis dependent upon the position of the plunger 30a, and: in

turn is dependent upon theaxial adjustment of the particula r stop screw 35 which is then engaged by the plunger. 1

' In the arrangement illustrated by the drawings, provibrought into alinement with the rate valve plunger. 30a

when the turret 1 5 is in successive ones of its stations.

Thus, by axially threading or adjusting the several stop screws 35' relative to the disk'36, the position of the rate valve plunger 30a whenthe associated solenoids-RT ,is

.de-energized may be preselected. Since the position of this plunger 730a determinesthe size of theqrestn'ctiorr presented by the rate: valve 30 in the line 28 (FIG: 7) the magnitudeor value. of the feed rate whichobtainswhen the 'turret'is in each or its stations may be preselected,

To aid in; making the cycles of turret movement occur automatically in succession,1a control switch CSF. is ara ranged to be actuated when the turret is in its home posi tion, that switch being efiective to initiate forward movement. As shown best in FIGS. 2 and 3, the switch CS-F is mounted on the bracket 48 opposite an adjustable actuating screw 53 carried by the yoke 21. The screw 53 engages and actuates the switch CS-F only when the turret 15 is in its fully retracted position.

The main shut-E valve 25, physically mounted in the bracket 44, may be opened by shifting a manual control lever CL and an associated link rod. The valve is held open by a latch (not shown) but may be closed at any time to stop movement of the turret by shifting the lever CL in the opposite direction.

With the foregoing-in mind, the organization of the electrical control circuits to produce a standard cycle of turret movement may now be understood with reference to the following description of one operational sequence. Let it be assumed that the valve 25 has been latched open and that the turret 15, having substantially completed one cycle of movement, is traversing rearwardly but has not yet reached its fully retracted position. Under these conditions, the valve 30 (FIG. 7) is in its wide-open condition, and the valve 26 is in its reverse condition so that pressure fluid is being supplied to the left end of the cylinder 20a and is being returned from the right end of that piston to the sump 24.

Under these circumstances, a reverse relay having a coil RR (FIG. 8) will be energized and sealed in because the forward control switch CS-F and the time delay relay contacts TDR-Dl and TDR-D2 will be closed, for a reason to be explained presently. A dwell relay DR will thus also be energized. The reverse relay RRZ will be closed, and the dwell relay contacts DRZ will also be closed to complete an energization circuit for the reversing solenoid SR. With this solenoid energized, the direction valve 26 Will be in its reverse condition, as previously explained. Further, the rate valve solenoid SRT will be energized through closed dwell relay contacts DRl and normally closed back-feed relay contacts BFR2.

Then, when the turret reaches its fully retracted posi tion, the actuating pin 53 will trip the forward control switch CS- F. As a first result, actuation of the switch CS-F breaks the energizing circuit for the reverse relay RR (FIG. 8) and the time delay dwell relay TDR-D. Accordingly, the time delay dwell relay contacts TDR-Dl will open to de-energize the dwell relay DR. Thus, the three relays RR, TDR-D and DR are dropped out. The reverse relay and dwell relay contacts RR2 and DR 2 both open so as to d e-energize the solenoid SR, taking the direction valve 26 out of its reverse condition.

Moreover, actuation of the forward control switch CS-F completes an energization circuit through. the normally closed jog contacts 12 tor the coil RTR of a rapid traverse relay. This latter relay thus picks up and seals in through its own contacts RTR-l and the normally closed control switch CS-'FD.

It will, therefore, be apparent that the normally closed reverse relay contacts RRI are reclosed by the de-energi- V zation of'the relay RR, and the normally open rapid traverse relay contacts R'IR3 are closed by the energization of the relay RTR. Thus, even though the contacts DRl open in response to de-energization of the coil DR, an energizing path is maintained through the contacts RRl and RTR3 for the rate valve solenoid SRT. The latter remains energized and the valve 30 remains in its wideopen condition so that :further movementsof the turret will take place at traverse rates. a p

Finally, when the reverse relay R-R was de-energized, its own normally closed contacts RR4 reclosed, thus-creating an energization path throughthe normally closed relay contacts PR3 -for the forward solenoid SF of the direction controlling valve 26. This latter valve is thus switched to its tforward condition so that'the turret then advances in a forwarddirection and at a traverse rate.

When the turret 15 has been traversed forwardly through a first predetermined distance determined by the setting of the particular dog 45 which corresponds to the station then occupied by the turret, that dog 45 will engage the roller 46 (FIG. 2) and actuate the feed control 5 switch CS ED. The normally closed contacts of this switch (FIG. 8) will therefore open, thus breaking the sealing circuit for the rapid traverse relay RTR and cans ing the latter to drop out. As a result, the rapid traverse relay contacts RTR3 re-open and tie-energize the rate valve solenoid SRT. The latter solenoid cannot be otherwise energized because the contacts DR I are now open, as are the relay contacts NR2. With the de-energization of this solenoid SRT, the biasing spring 300 (FIG. 7) shifts the rate valve plunger 343a to the right until it contacts the particular stop screw 35 ialined therewith. A restriction of a size determined by the setting of that stop screw is thus inserted in the hydraulic line 28, making it more difiicult tor fluid to pass through that line from the left end of the cylinder 243a. Accordingly, the turret 15 then continues its forward movement but at a slower feed rate determined by the setting of the stop screw engaged with the rate valve plunger 30a. It is at this point that the cutting tool carried by the turret engages the workpiece in the chuck H4 and begins the actual cutting operation.

When the turret has been advanced at a feed rate through a second predetermined distance for completion of the cutting operation, the tip of the screw 49c associated with the dog 49 carried in the uppermost position on theshaft will strike and deflect the finger 50, there- 30 by actuating the reversing control switch CS-R (-FIG. 2) As shown in FIG. 8, actuation of this latter switch CS-R creates an energizing path for the reversing relay RR and the time delay dwell relay TDR-D. At this point, it will be assumed that thetime delay dwell relay TDR-D has in unison with those of the reversing relay In response to energization of the reversing relay RR, its normally closed contacts *RR4'will open, and thus deenergize the. forward solenoid S- F. Moreover, energization of the time delay dwell relay TDR-D results in closure of the contacts TDR-Dl, completing an energization path for the dwell relay DR. With this, the dwell relay contacts DRZ in series with the now closed reversing relay contacts RRZ energize the reversing solenoid SR, so that the valve 26 is set to its reverse condition. Further, pickup of the dwell relay DR results in closure of the contacts DRd so that the rate valve solenoid S-RT is energized to shift the valve 30 to its :wideopen condition; Accordingly, the direction of the turret is reversed so that it retracts, .and the rate valve is moved to its wide-open condition so that the retraction proceeds at a traverse rate.

When the turret reaches its fully retracted position, the foregoing cycle of operation will repeat, the turret having been indexed to its next rotational station as an incident to the retraction thereof. Thus, the standard cycle of operation will repeat over and over with the turret being indexed between successive cycles. As an important feature, the distance of ronward traversing is preselected or predetermined individually for each turret station by the setting of the several dogs lengthwise along the shaft 40. In like manner, the distance of forward'ieeding movement of the turret is preselected or predetermined for each station thereof by the setting of the corresponding dogs 49 lengthwise of the shaft 49. Finally, the magnitude or value of the feed rate is pre-program-med for each turret station by the setting of the corresponding stop screws 35 carried by the indexed disk 36.

If it is desired to stop the operation of the lathe after the completion of the cycle of movement at any one or any combination of the turret stations, it is only necessary to insert a projection, such as a screw 55, into the corresponding tapped holes 56 which are angularly spaced about the shaft 40. If a screw is located in one of these holes $6 so as to be brought to a predetermined angular position when the turret is at a particular one a timing cycle of zero seconds so that its contacts actuate I r s a of its 1stations,-that screw will, upon retraction of the a1ly indexed in step with the jecting means is sodisposed on the periphery. of that turret, engage and deflect a lever 57 which u'ipsthe latch (not shown) to close themain shut off valve 25. With the closure of this valve, it will be apparent from FIG. 7 that further movement of the turret will be terminated because no pressure fluid from thepump. 22 can reach the hydraulic actuator 35%. a l V I At this point it will be appropriate. to note thatin the preferred embodiment of the invention, many of the control components for the present system can'be mounted in a portable control cabinet as (FIG. 1).. In thelower portion of, this cabinet thefluid sump 24, the, pump 22 and its driving motor, the reversing valve 26, and all of the various time delay and control'relays mentioned in 7 connection with FIG. 8 can be located. Connections from the components in the cabinet 69 can be made to the components mounted on the lathe it? by detachable 1 these disks is provided with six angularlyspaced openlugs adapted to receive means such as projecting dog 7 screws or pins. ,The disk Da is provided with one such hydraulic lines 61 and 62, and bya multi-conductorf,

cable 64 which carries the necessary wiring connections to the several control switches. V 7 Apparatus and operation for prodticingdwelling cycles In the foregoing description of the controls and their itwas assumed that the time delay relay TDReDjshown turret. Moreover, a proindexed member as to actuate and close its switch when the turret is at a corresponding rotational station.-

' Asillustrated in FIG. 3,.the sleeve 52,. axially station-.

ary, buti rotationally indexed with the turret, is made to carry six disks Da through D these disks being axially stackedtogether to form a. composite drum. Each of projecting mm screw which isarranged to actuate the switch DSTtz when the turret is in its first'rotational station (see FIG. 2). In asimilar fashion, each of the disks Db through 13 carries one dog or projection which is so disposed as to actuate. the switches DSTb through DS'l when the turretfis in its second through its sixth. stations, respectively. Thus, it willbe apparent that when the turret is at its fifth station, the timing switch DSTe operation for producing-a standard cycle ot operation,

in FIG. 8 was set to provide a zero time delay so'that there was no dwelling action. It is highly desirable in certain operations, however, for the tool carried-by the c turret to dwell atits greatest point'of penetration for a predetermined :period of time in orderto clean up the bottom of the cut.. The required duration of this dwell period depends upon the particularnature of the tool in use on any given station 'of the turret, and upon the material of the workpiece. In accordance with one feature of the invention, therefore, niot only is provision made to cause the turret to dwell at itsfarthest point of advance, but provision is made to individually predetermine and adjust the duration of the dwell period from Zero up to a fairly long time interval, e.g., 15 seconds, which will be obtained at each or any of the'turret sta- I tions;

' In order to make this possible, the-time delay dwell relay TDR-D is selected. to be of the type which utilizes an adjustable time period determining element. In the preferred form, this-delay relay-is a standard electronic" type relay whichutilizes a resistance-capacitance series circuit to measure off time intervals by the timed charging or discharging of the capacitor.v Since such electronic time delaycircuits utilizing resistance-capacitance circuits are well:known to those skilled in the art,-it will he sutfi-' cient here simply to. indicate that the time period between the instant of energization of such a relay and the'instant at which its contacts are actuated, depends uponthe value of the resistance whichfis connected in series with a 'ca- .pacitor. To make it possible to individually adjust the duration of a dwell period which occurs when the turret is at each of its several indexed stations, a plurality of adjustable time-determining elements in the formFof a plurality of adjustable resistors are successively connected:

operationally in'the circuit of the electronic time delay relay.

sistors Ra through Rf in response'to closureofa'cor-f responding one of the switches DSTa through DST].':-

" In order to actuate a particular. one of the switches-* DSTa through 'DSTfwhen the turret 15 isin a corresponding one of its indexed positiongleachfof these.

switches is associated with a member which is rotationshown in FIG. 9 'will be closed to connect the adjustable resistor Re incontrolling circuit relation with the capacitor C of the electronic time ,delay dwell relayTDR-D."

Since'the-resistor Re can be individually adjusted as to its effective value, the operator of the turret lathe 10 can preselect in advance the duration of the dwell period which will take place when the turret is at its fifth station.

The foregoing applies, equally well to each of the other.

. stations of the turret.

As shown particularly in FIG. 1; each of the dwell period-determining resistors Ra'through Rf is mounted in the control cabinet with an associated external knob so that the settingsof these six resistors may be quickly and conveniently made'by an operator to pre-prograrn the dwell periods (say from O to 15 seconds) which are desired at eachof'the six turretstations.

V For an understanding of, h-ow the controls actually crer ate a dwell period, reference may again be made in FIG.

8. It will be' recalled from the preceding description of operation for a standard cycle vof'turret movement that the time delay relay TDR-D was de-energized when the I turret reached a' fully retracted position. As thelturret,

then-reversed its movement and began to traverse fora Wardly, the forward control switch CS-F was released by the pin 53, and thus deactuated. However, the reversing relay RR and the time delay relay TDR'D were not again energized because the contacts TDR,-D2 were then open.

Now, when the turret reaches the end of its speeding V movement through a second predetermined distance and the second dog 49 on the shaft 40 deflects the finger 50 1 to actuate thereversing control switch CSR '(FIG. 2).,

that switch is closed to energize (FIG. 8) *the' reversing RR and the coil of the time delay relay TDRD.' The reversing relay RR is thus picked up immediately, but

the time, delay 'dwell relay TDR-D'will not actuate its 'In the preferred arrangement, where the turret has 1 six indexed stations, six separateadjustable resistors Ra contacts until after a predetermined interval deter-mined by the setting of the particular one of the timing resistors which is then connected in circuit with the capacitor C by the disk switches DSTa throughgDSTf. .Thus,ractuatron of therreversing relay 'contactsgcauses its normally closed contacts'RR4 to open and de energize thetonward' solenoid SF. "This resultsin centering of-the reversing valv'e plunger 26:; so that pressurefiuid cannot pass there} 7 through. The piston Zt b'and the turretlS'thus come to ahalt; I

Afterthetime' delay "dwell relay TDR-D- times out,

a period which is determined by the setting of thejcor- 7 respondingrone of the resistors Ra through Rf, then its con.

at the. end of a predetermined"dWel p fvalve f 26 is set to its reverse condition and the turret begins its retracting motionJ 'It will also be recalled that energizatacts will actuate. It is only then that the contacts TDR-fl D1 close to energize'the dwell relay DR,'andthus cause the contacts DR-Z' to close andcomplete, an energizing path for thejrever sesolenoid SR=ofthe valve 26, vI'hns;

tion at the dwell relayRD results in closure of the cone tacts DR-1 to energize the rapid traverse solenoid S-RT, setting the rate valve 39 to its open position so that the turret proceeds rearwardly at a traverse rate.

Controls and opefatz'on for boo/ feeding cycles In most machine operations it is possible to feed the turret and the tool carried thereby slowly into the work, and then traverse them out of the work, as will be accomplished by the standard cycle of turret movement described above. However, in certain other machine operations, it is necessary to feed the tool into the work,

feed the tool slowly back until it clears the work, and only then move the turret at rapidtraverse in a reverse direction. For example, in boring operations, if the tool is traversed reversely out of the bore, the cutter will leave a spiral mark. To avoid this, the cutter is fed rearWa-rdly out of the hole so that the cutting tool finishes the inner surface of the bore and leaves it unmarked.

In accordance with one feature of the present invention, provision is made to modify the controls previously described so that a 'backfeeding cycle of operation takes place when the turret is in any preselected ones of its rotational stations. To bring this about, normally deactuated means are interconnected in the control system to modify the operation thereof, and a member indexed in step with the turret is caused to actuate the modifying means when the turret is at certain stations preselected or preprogrammed by the operator,

In he preferred embodiment here illustrated, all that is required is an electric switch and means to actuate it when the turret is in preselected stations, together with one or more auxiliary relays. As shown best in FIGS. 2, 3 and 4, an additional circular'd-isk D-BF is mounted on the shaft 52 so as to be rotationally indexed instep with the turret through the turret shaft 15a, the gears 37, 39 and the splined shaft 41. That backfeeding control disk, D-BF, is provided with means spaced about its periphery to receive project-ions which are positionable to actuate an electric switch DS-BF located physically in proximity to the disk. The projecting means may take a variety of forms so long as they are selectively movable between operative and inoperatively positions. In one simple form, the disk D-BF is provided with a plurality of six holes a spaced around its periphery which are adapted to receive removable pins or screws 65. As shown in FIG. 4, the disk D-B-F has been provided with two such projections 65 at the holes corresponding to turret stations :2 and e. When the turret is at corresponding rotational stations, therefore, the pins 65 will engage a finger 65 and depress the latter to actuate the backfeeding disk p 7 1Q and seals in'the reverse relay RR, and energizes thetime delay dwell relay TDRD.. Actuation of the latters contacts TDR-D1 results in pickup of the dwell relay DR and closure of the contacts DRl. However, because the contacts BFRZ are now open, the rate valve solenoid S-RT will not be energized as previously described for the standard cycle of movement. Therefore, the rate valve 39 (FIG. 7) will continue to have its plunger 36a biased by the spring 30c into engagement with the stop switch =DS-BF. When a projection 65 has been provided on the disk D-BF to predetermine that backfeeding shall take place at a particular turret station, then the switch DS-BF will be actuated and will create a modification in the control apparatus which may now be described with reference to FIG. 8.

Referring to FIG. 8, let it be assumed that the back 7 feeding disk switch IDS-BF is now actuated by a projec tion 65 on the associated disk D-BF. The operational cycle of the control equipment proceeds as previously described for the standard cycle. However, after the first dog 45 on the shaft 49 actuates the feeding control switch CS-FD, so that the rapid traverse relay RTR is de-energized, and the turret is advancing at a feed rate, the contacts RR]. and RTR2 will be closed. "This completes an energizing circuit through. the backfeed disk switch DS- BF to the coil of abackfeed relay BFR. Upon energization of that relay, its own contacts BFR 1 close to create a sealing circuit through the normally closed contacts of the feeding control switch CSFD Also, pickup of the backfeed relay BFR results in opening of the normally closed contacts BFRQ.

Then, when the turret has reached its point of maximum forward travel, the reversing control switch. CSR is actuated by a dog 4% on the shaft 40. This picks up screw. 35. Any movement of the turret must proceed at a feed rate which is determined by that particular stop screw. Thus, with the de-energization of the forward solenoid S-F'and energization of the reverse solenoid S-R, as previously described, the turret begins to retract, but at a feed rate rather than at a traverse rate.

As soon as the turret is retracted to the point at which the tool is clearof the work, i.e. to the point at which forward feeding was initiated, then the dog 45 on the shaft 40 will engage the roller 46 and actuate the feed control switch CS-FD (FIG. 2). Actuation of this switch, as shown in FIG. 8, will open its contacts and break the sealing energization circuit for the backfeed relay BFR. Accordingly, the contacts BFR2 will reclose and establish an energization circuit through the already closed contacts DRl for the rate valve solenoid S-RT. Energization of this solenoid will reposition the plunger of the valve 30 (FIG. 7) to its wide-open position, so that further rearward movement of the turret will proceed at a traverse rate.

The cycles of operation will repeat over and over as previously. described but the special cycle involved in backfeeding of the turret 15 will occur only when the latter is in those particular stations corresponding to the angular positions of the backfeeding disk D-BF which have been provided with projections 65 to actuate the backfeed switch DS-BF. With this arrangement, an operator of the turret lathe may pro-program the control equipment so that backfeeding will occur automatically at those partic ular stations which he selects by the insertion of the projections 65.

' Controls and operation producing a floating cycle for thread cutting When a given tool carried at one of the turret stations is a thread-cutting die, it is necessary that the die thread itself onto or into the work. Thus, it is not desired to forcibly and positively feed the turret toward the work held in the chuck 14, but only to supply enough force by means of the main hydraulic actuator 20 to overcome the inertia and frictional resistance to movement of the turret slide 16. For thread-cutting operations, therefore,

the turret is made to float so that the die is not forcedv into or out of the work.

In keeping with another aspect of the invention, provision is made to modify the controls previously described so that a floating cycle of operation will take place wheneverthe turret is in any preselected one of its several stations. Normally deactuated means are interconnected with the control system such that when they are actuated by a member indexed in step with the turret, they will change the operational cycle previously described and cause the turret to float during those periods when it would otherwise, under a standard cycle of operation, be forcibly fed.

In the preferred'form here shown, means are provided to reduce the output pressureof the source or pump 22 whenever feeding would othelwise be taking place during a standard cycle, so that the hydraulic actuator receives only enough power to barely move the slide 16 and turret 15 toward or away from the work. As shown in FIG; 7, such pressure reducing means take the form of a normally closed restricting .valve'70 having a plunger 70a with a passage therethrough. The plunger 70a is normally biased by a spring 7012 out of. alinement with ports in a casing 70c. The valve 70 is connected be tween the output :side of pump ciated with that valve. is a floating solenoid SFL which i T; a

2 and thesump 24. Assowhen energized shifts the plunger'wa to the right against the biasing spring 76d, thus bringing the passage in the plunger into 'alinement with the casing ,ports and permitting fluid to pass through the valve, so that the pressure on the output side of the pump 22 isconsiderably reduced.

In order to make it possible for an operator to preprogram or preselect a floating cycle ofturret movement to occur when the turret is in any of its rotational stations, an additional disk D-FL is mounted on the sleeve 52 (FIG. 3) so'as to be rotationally indexedjin s'tepwith the turret 15., The disk D-FL is constructed in a manner substantially identical to that previously'described fo'rthe backfeeding disk D-BFrit is providedwith selectively positionable projections, such as fthe projections 65- in FIG. 4, which are arranged-to actuate a floating disk switch DS-F (PEG. 2) disposed in physical proximity to that disk. Thus, an operator may'by suitably positioning a number of projections on the periphery of the disk D-FL cause the floating disk switchDS-F to be actuated when the turret is at those particular stations for which 7 a floating rather than a standard. cycle of movement is desired. a

The elfect'and the change in the operation of the con- 7 IE2. at the end of the floating injfaction and the tripping of the reversing control switch CS-R by the dog 49 on the.

shaft 49 which results in energization of the reversing relay RR, opening of the normally closed contacts RRI will not de-energize the tapping relay TR. That tap-ping 7 relay remains energized through the sealing circuit previously described. Accordingly, the output pressure. of the pump 22 is maintained at a relatively low valuejso that as-the turret begins its reverse movement, it receives a suflicientforce-from the actuator 24? only to overcome its inertia and friction. The die thusTloats out of the a work, the direction of rotation 10f the chuck '14 having been reversed by appropriate control means (not shown). Then, when the turret has retracted to the point at which the floating in operation began, the dog 45 on the shaft 43 will again actuate the feedcontrol switch CS-FD. As shown in FIG. 8, actuation of this latter switch interrupts the sealing circuit for the tapping relay TR. so that the latter drops" out, opening its contacts TRZ and deeenergiz ing the solenoid SeFL. Thevalve 70 is thus reclosed so that the full output pressure of the pump 22 is again avail.-

trol system which isbrought about by the actuation of the floating disk switch DS-F may be understood with reference to 1 16. 3. With the switch contacts DS-F closedin FIG. 8, the cycle of operation will proceed as previously described except that when the turret has rapidly advanced to'the point at which the dog 45 on the shaft 49 actuates the feed control switch CS-FD (and thus causes the rapid traverse relay RTR to be de-energized), the coni tacts RTR'. .will recluse and establish anenergization circuit for a tapping relay TR through the contacts RRI, RRZ and DS-F.

the work held by the chuck 14, rather than being forcibly I fed as inn-the standard cycle previously described. The. thread-cutting tool carried by the turret at that station 'will thus thread itself orpull itself into the work.

It may be assumed for the moment that the threadcutting tool carried by the turret is anexternal threadcutting die of the type which automatically opens or releases when it reaches the end of the shank to be threaded. When the turret has advanced to the end of the threading operation, the dog 49 on the shaft 40 will actuate the reversing control switch CSR and will immediately ener- "gize' the reversing relay RR, as previously described; This, in addition to setting the. direction valve 26 inits reverse condition, and setting the rate valve 30 'to its'wide open or traverse condition, will result in opening of the normally closed contacts RRI so'that the tapping relay TR will be de-energized.

travense the turret rearwardly.

In tapping holes or internal threads, howeverpit is nec-' essary for the turret to bothffloat in and float out.

For this operation, amanual-selector switch MSS, located on the control cabinet 60 F-1G 1) and connected in the circuit shown by FIG. 8, is closed. When the tapping relay TR is energized, as previously explained, .itsrown contacts TRI will close to create a sealing circuit through e the normally closed feed control switch .C SFD-and the manual selector switch MSS. Under these circumstances,

7 Pickup of the tapping relay TR will result in closure of its normally open contacts TRZ (at the bottom of FIG. 8), and thus'in energization of the floatdetermined. distance. rapidly retracted to its home position.

able to traverse the turret rearwardly to its home position. Of course, as an incident to that full retraction of the turret, the turret is indexed and the floating control disk D -FL is correspondingly indexed. If no projection is at I the next station on that disk to actuate the floating disk switch DS F, thenthe next cycle of turret movementwill proceed in the usual fashion.

Reciprocating cycle for deep hole drilling-z In some instances it may be desirable to have the turret: 1 15 carry a relatively small diameter bit for drilling'relzu' tively deep holes in a workpiece carried 'by the chuck 14h.

As relatively deep holes are drilled in a' workpiece, it is desirable to retract the bit fromthe hole periodicallyto remove accumulated ch'ips Otherwise, the ,frictionand heat may destroy or at least dull the bit; Yet, in periodicallywithdrawiug'the .bit from a hole being drilled, it is desired to effect the withdrawal as rapidly aspossible and to reinsert the bit at a rapid rate 'untilit reaches the bottom of the partially drilled-holeJ The-desiredvcycle' of turret movement for deep hole drilling thus entails traversing the turret in a forward direction from its home posi-' tion through a first predetermined distance to bring the hit up to the workpiece, feeding the. bit into the work-- piece 'for a short distance or for a ShOI'lllllTlC interval,

traversing the turret rearwardly untilthe hit just clears the workpiece, traversing the: turret forwardly until the drill almost reaches the endcf the partially completed .hole, then feeding the turret forwardly for another short a distance or time period. This reciprocationoperation is repeated until the. desired depth of'hole is reached, i.e., the turret has been fed cumulatively through a second pre- 7 In'accorda'n'ce' with an important feature of the inventron, provision is made to so modify the controls previously described that such a reciprocating cycle for deep Its contacts TRZ thus open to dc- .7 energize the solenoid S'FL,' so thatthe valve 76 recloses and the full pressure of the pump 22 is again available to r hole drilling takes place when the turret is in any preselected ones of its stations. -To makethis-possible, only a relatively slight addition-in the way of. apparatus; and. control components is required andyet the operator can pro-program the entire control system so that a reciprocat- .ing cycle is obtained automatically when the turret reaches any predetermined one or' more of its rotational stations.

1 For efiecting such a reciprocating cycle of turret movement, means such as a pull-out arm ismounted for movement parallel to the path of'the turret. As'here 7 shown in FIGS; 1; 2 and 6, the arm 75 takes the form of arhollow tube which isslidable longitudinally of the lathe bed .12 through the spaced brackets 44 and 48. Fixed near the forward end of thearm 75 is a yoke 76 to which a a second guide shaft 77 'rnay be fixed, the latter being" slidable in a sleeve 78 extendingbetween the brackets 44 and Y H After this, the turret should be Means are provided for moving the arm forwardly in unison with the turret 15 as the latter advances when it is many selected one or more of its rotational stations. For this purpose, a circular collar 80 is mounted rigidly on the forward end of the splined shaft 41 and provided with a plurality of circularly spaced openings 81 in its periphery. Means such as removable screws or pins 82 are adapted to be received selectively in the difi erent openings 81. Since the collar 80 is rotationally indexed in step with the turret 15, insertion of a pin 82 in a particular one of the holes 81, will bring that pin into alinement with a finger 84 depending from the arm 75 whenever the turret is at a particular preselected one of its stations. With the pin 82 in position illustrated by FIG. 6 as the turret advances in a forward direction, the pin will engage the finger 84 and pull the arm 75 forwardly with the turret.

To hold the arm 75 in a position which establishes the point of farthest advance of the turret even though the latter is retracted, means are provided to prevent rearward or reverse movement of the arm. For this purpose, a one-way brake device 85 is mounted in the bracket 48 and comprises a stationary sleeve 86 having a tapered throat 88. Disposed concentrically within the sleeve 85 is a carrier tube 89 formed at its forward end with a plurality of apertures which loosely hold captive a plurality of spherical elements or balls 90. The sleeve 89 is biased to the left relative to the throated member 86 by a compression spring 91, and slidably extends through the bracket 44. Thus, under normal conditions, the balls 99 are wedged tightly between the inner surface of the tapered throat 88 and the outer surface of the arm 75. The latter cannot move rearwardly (to the right) since that would Wedge the balls 90 even more tightly in the tapered throat. However, the arm 75 can be pulled forwardly (to the left) because this tends to move the balls 90 into a wider portion of the tapered throat 88 so that they can spin freely.

For returning the arm 75 to its original position, an elongated tension spring 94 is disposed within its interior and connected at its rear end to the sleeve 89. Thus, as the arm 75 is pulled forwardly, the spring 94 is placed under tension, but cannot pull the arm 75 rearwardly because of the locking action of the one-way brake 85.

. V 14 only after the pin 82 moves forwardly a fraction of an inch beyond that point of initial engagement.

It would be understood from the foregoing, therefore when a reciprocating cycle for deep hole drilling is desired at a certain station or" the turret, the operator preprograms this by inserting one of the pins 82 into the corresponding hole 81 of the disk 80. When the turret is at the desired station, the pull-out arm 75 will be advanced with the turret but will remain at the point of farthest advance even though the turret subsequently retracts and the pin82 retreats from the finger 84. However, when it is desired to return the arm 75 to its original position, the solenoid SBR is energized to release the one-way brake 85. and permit the tension spring 84 to retract the arm '75. The switch CS-PO is actuated by the collar 84:: whenever the pin 82 is engaged with the finger 84 and the turret is advancing in a forward direction.

With the foregoing in mind, the modified operation forproducing a reciprocating cycle of turret movement may now be described with reference to FIG. 8.

The reciprocating cycle of turret movement begins in the same fashion as the standard cycle. The turret advances in a forward direction at a rapid traverse rate, the pin 82 in the collar 80' engaging the finger 84 so that the switch CSPO is actuated and the sleeve 75 is moved forwardly in unison with the turret. During this initial rapid advance of the turret, this actuation of the pull-out control switch CS-PO does not energize the time delay reciprocation relay TDR-R (FIG. 8) because the rapid traverse relay RTR is energized and the contacts RTRZ are open. When the first dog 45 on the sleeve actuates the feed control switch CS-FD, and thus causes de-energization of the rapid traverse relay RTR so that the contacts RTRZ reclose, the time delay relay TDR-R is ener gized through the actuated switch CSVO as the forward feeding operation begins.

The purpose of the time delay relay TDR-R is to terminate forward feeding of the turret and initiate retraction of the tool at the end of a short time period.

For releasing the brake and permitting the spring 94 to return the arm 75 all the Way to its home position, a brake release solenoid SBR is mounted on the bracket 44. That solenoid has an armature 95 disposed to deflect a lever 96 which will engage the right end of the sleeve 89 and shift the latterto the left against the bias of the spring 91. When the solenoid is energized, therefore,the sleeve 89 will shift to the right and move the balls90 into a wider portion of the throat 88. Thus, the balls will lose their grip and the spring 94 can retract the arm 75 to its home position.

As an important part of the apparatus for modifying the control system to produce a reciprocating cycle of turret movement, a switch is arranged to be actuated when the turret is at preselected stations and is moving the arm 75 forwardly. As here shown, a pull-out control switch CS-PO is mounted on the yoke 76 and is arranged to be actuated when the pin 82 is engaging the finger 84. For this purpose, the finger 84 depends from a collar 844 which is slidably mounted on the arm 75. This collar 84a is normally biased to the right into abutment with the yoke 76 by a compression spring 98; However, as the pin 82 engages the finger 84, it shifts the collar 84a forwardly relative to the arm 75 so that the collar cams finger associated with the switch CS-PO and actuates the latter. As the collar 84 advances further relative to the arm 75, it engages a thimble 99 rigidly fixed to the arm, and thus thereafter moves the arm forwardly in unison with the turret. By this arrangement a lost motion connection is established between the pin 82 and the arm 75, the switch CS-PO being actuated as soon as the pin 82 engages the finger 84 and the arm 75 being advanced Thus, when the time delay relay TDRR times out and picks up, its own contacts TDR-Rl close to create a sealing circuit through the normally closed feed control switch CS-FD. Moreover, its contacts TDR-RZ close to energize an auxiliary relay PR through the normally closed contacts RR4. Pick-up of the relay PR results in the opening of the normally closed contacts PR3 so that the forward solenoid SF is de-energized after a predetermined time delay, and before the turret has advanced sufiiciently to feed the drill bit fully into the work. Simultaneously, the relay contacts PR2 close so that the reverse solenoid SR is energized through those contacts and the normally closed contacts PR4. Thus, after the turret has advanced for only a relatively short feeding period, its direction of motion is reversed in response to pick-up of the relay PR after timing out of the reciprocating time delay relay TDR-R.

Still further, pick-up of the relay PR results in closure of its contacts PR1 and energization of another auxiliary relay NR through the now closed contacts RR1 and RTR2. The relay NR seals-in around the contacts PR1 through its own normally open contacts NR1 and the normally closed contacts of the switch CS-PO. The latter is. deactuated at this time because the turret is moving in a reverse direction so that the pin 82 (FIG. 6) has moved rearwardly away from the finger 84, the arm being held at its point of farthest advance by the one-way brake device 85. Energization of the relay ,NR also results in closure of its contacts NR2 so that the rate valve solenoid SRT is energized and the retraction proceeds at a rapid traverse rate rather than at feed rate.

With the slide thus being moved reversely at traverse rate, when the dog 45 on the shaft 40 actuates the control feed switch CS-FD (at the point at which the original feeding motionbegan, and thus at a point Where the drill bit is clear of the work), the sealing circuit for the retinues to be energized ciprocating time delay, relay TDR-R will be broken.

That is, the contacts CS-FD in series withthe contacts TDR-.R1 will open and immediately drop outof the relayTDR-R. This results in opening of the contacts TDR-RZ, and de-energization of the relay PR. With this, the contacts PR3 reclose to energize the forward solenoid F-S While the contacts PR2 open to deenergi'ze the reverse solenoid S-R. Therefore, the valve 26 is set,

in its forward condition, and the turret moves forwardly, but at a rapid traverse rate since the solenoid S-RTconthrough the now closed contacts NR. 7

When the turret has almost reached the point of its previous farthest advance, that is, when the tip of the drill bit has almost reached the bottom of the partially drilled hole, the projection 32 will againengagethe finger 84' and actuate the pull-out control switchCS-PO. This breaks'the sealing circuit for the auxiliary relay NR, causing the latter to drop out so that its contacts NR2 open and ,de-energize the brake valve solenoids-RT; This shifts the rate valve 38 to its partially closed condition and changes the turret movement from traverseto feed rate. As the tool advances another fraction of an inch,'it contactsthe work,'begins drilling again withthe turret being-fedslowly into the work and the collar 84a abutting the .thimble 99 to advance the arm 75 therewith.- i It is to be remembered that when the. switch MSPO was actuated, it again established an energizing circuit for the time delay reciprocating relay TDR R, so'that the latter begins: another timing cycle.

feed and drilling for another predeterminedperiod, the time delay relay TDR-R will actuate its contacts and the.

After the forward distances, and means indexed withtthe turret for connect-.

7 elements independently of the turret feed rate and of foregoing operation will be repeated. Therefore, the drill V will be repetitively'reciprocated into. and out of the Work,

7 being retracted at'rapid traverse, advanced at rapid traverse 'to a point almost at the bottom'of the hole previously drilled, and then fed slowly for a predetermined period 'into the work. e i l V Finally, when the drilling has proceeded to, a predetermined depth established by the setting of thesecond dog d9 on the sleeve 40, that, dog will actuate the reversing control switch CS-R. When this occurs, the reverse .re lay RR and the time delay dwell relay TDR-D will both be actuated. Accordingly, the contacts RRl will open to make certain that the relays NR and TDR-R are both trol system for 'moving a lathe turret presents a high der a r 15" 7 fully utilized and only modified by appropriate interconnections in orderto achieve'the other special cycles of movements, Important, too, is the advantage that the dwelltime period may be individually adjusted and'pre selected for each of the turret stations.

I'claim:

1., In a lathe having a turret movable alongra linear path, reversible power means for advancing and retracting the turret, and means for indexing the turret to sue:

cessive ones of a plurality of rotational stations "as an incident to retraction of the turret, the combination comprising means for controlling the power mean's to execute, a standard cycle of operation consisting'of traversing forwardlythrough a predetermined distance, feeding forwardly through a second predetermined distance, and then traversing reversely to the original position, said controlling means including electrical time (lelay'means responsivejto termination of the forward movement of said turret for creating a dwell period'between the ,ter mination of the forward feeding and'the initiation of the 1 reverse traversing of the turret, and a plurality of electricaltimerperiod determining elements each oflwhich is adjustable for determining the duration of said dwell period independently of the feed rate of said turretand also independently of the length of saidpredetermined ing a dilferentone of said elements into controlling rela-,

'tion with said time delay means when the turret is in each .of its stations, so that the dwell period for each'station' of the turret may be preselected'by adjustment ofv said the distances through which the turret moves." I V 2. In a lathe having a turret movable along a linear path, reversible powervmeans for advancing and retracting the turret, and means for indexing the turret to suecessive ones of a plurality-of rotational stations as an incident tolretraction of the turret, the combination comprising mcans for controlling'the power means to execute a standard cycle of operation consisting of traversing] forwardly through a predetermined distance, feeding forwardly through a secondpredetermincd distance, andthen traversing reversely to the original position, said controllingineans including a time'delay relayand means connecting the same to create 'adwell period between the termination of theforward' feeding andrthe initiation of the reverse traversing-of the turret, said time delay relay having a resistance-capacitance circuit for measuring'off time periods, a plurality of adjustable resistors, a plurality of switches for individually connecting respec: l UVQOI'leS of said resistors in said time delay relay circuit,

' and means indexed with the turret for actuating one of,

said switches when the turret is in a corresponding one of its stations, so that the dwell period at each turret stagree of versatility in that'a standard cycle, a dwell'cycle,

a backfeed cycle, a floatirig cycle, or a reciprocating cycle of turret movement can-be obtained. Moreover, any one of these cycles may be pre-programmed to occur, at any one or more of the turret stations automatically. When the turret reaches a .given station the operator needinot interrupt the machine to make adjustments. All of this is done intadvance. One important advantage of the present system is that the apparatus and control components for providing just a standard cycle of turret movement are tion is predetermined bythe setting of'the corresponding resistor. t V

, References Cited by the Examiner I 7 UNITEDUSTATE S PATENTS 1,909,165 5/33 Burrell L 29'42 2,034,562 6/37 Schafer 7732.5 l

2,a93,270-' 7/59 Hodgson et a1. '77' 2s,- .WlLLlAM W; DYER, JR., Primary Examiner,

BAILEY, Examiner, 

1. IN A LATHE HAVING A TURRET MOVABLE ALONG A LINEAR PATH, REVERSIBLE POWER MEANS FOR ADVANCING AND RETRACTING THE TURRET, AND MEANS FOR INDEXING THE TURRET TO SUCCESSIVE ONES OF A PLURALITY OF ROTATIONAL STATIONS AS AN INCIDENT TO RETRACTION OF THE TURRET, THE COMBINATION COMPRISING MEANS FOR CONTROLLING THE POWER MEANS TO EXECUTE A STANDARD CYCLE OF OPERATION CONSISTING OF TRAVERSING FORWARDLY THROUGH A PREDETERMINED DISTANCE, FEEDING FORWARDLY THROUGH A SECOND PREDETERMINED DISTANCE, AND THEN TRAVERSING REVERSELY TO THE ORIGINAL POSITION, SAID CONTROLLING MEANS INCLUDING ELECTRICAL TIME DELAY MEANS RESPONSIVE TO TERMINATION OF THE FORWARD MOVEMENT OF SAID TURRET FOR CREATING A DWELL PERIOD BETWEEN THE TERMINATION OF THE FORWARD FEEDING AND THE INITIATION OF THE REVERSE TRAVERSING OF THE TURRET, AND A PLURALITY OF ELECTRICAL TIME PERIOD DETERMINING ELEMENTS EACH OF WHICH IS ADJUSTABLE FOR DETERMINING THE DURATION OF SAID DWELL PERIOD INDEPENDENTLY OF THE FEED RATE OF SAID TURRET AND ALSO INDEPENDENTLY OF THE LENGTH OF SAID PREDETERMINED DISTANCES, AND MEANS INDEXED WITH THE TURRET FOR CONNECTING A DIFFERENT ONE OF SAID ELEMENTS INTO CONTROLLING RELATION WITH SAID TIME DELAY MEANS WHEN THE TURRET IS IN EACH OF ITS STATIONS, SO THAT THE DWELL PERIOD FOR EACH STATION OF THE TURRET MAY BE PRESELECTED BY ADJUSTMENT OF SAID ELEMENTS INDEPENDENTLY OF THE TURRET FEED RATE AND OF THE DISTANCES THROUGH WHICH THE TURRET MOVES. 